The Sloan Digital Sky Survey (SDSS) is an international scientific collaboration that has created the most detailed three-dimensional maps of the Universe. This project was divided into 4 phases, SDSS-I (2000-2005), SDSS-II (2005-2008), SDSS-III (2008-2014), and SDSS-IV (2014-2020). This work deals with the last Data Release (DR) 12 of the Baryon Oscillation Spectroscopic Survey [1]} and the DR16 of the extended Baryon Oscillation Spectroscopic Survey [2]}, subsets of SDSS-III and SDSS-IV, respectively.
Fig. REF  shows their redshift distributions.
We considered the catalogs of luminous red galaxies (LRGs) that cover the northen sky.
We do not consider the southern sky because the smaller number of galaxies does not allow for a robust determination of the BAO signal in thin redshift slices.
DR12-North offers a catalog with about 953 thousand LRGs with redshift up to \(z = 0.8\) , while DR16-North contains about 256 thousand LRGs within the redshift range \(0.6 < z < 1.0\) .
